Methods and apparatuses for controlling a manufacturing line used to convert a paper web into paper products by reading marks on the paper web

ABSTRACT

A method of producing a paper product. A paper web is formed on a paper machine. The paper web has a plurality of sections. The web is analyzed to perform at least one of inspecting and identifying properties. The web is marked with a plurality of marks. At least one mark is marked at each of the plurality of sections. Thereafter, the web is wound with a winder to form a parent roll. A paper rating is assigned to each section based upon properties in that section that are identified. The web is unwound from the parent roll on a converting line having a plurality of operational parameters. At least one of the plurality of marks is read with a mark reading unit. The paper rating associated with the at least one mark is obtained. At least one operational parameter of the converting line is changed based upon the rating.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional application of copending U.S. patentapplication Ser. No. 14/685,950, filed Apr. 14, 2015, which is claimspriority to U.S. Provisional Patent Application No. 61/980,022, filedApr. 15, 2014, and which are incorporated herein in their entirety.

FIELD OF THE INVENTION

Our invention relates to methods, systems, and marks for manufacturingpaper products such as paper towels and bathroom tissue. In particular,our invention relates to a method of controlling a manufacturing line toconvert a paper web into paper products and a converting lineimplementing this method. Our invention also relates to a mark for apaper web and a method of marking a paper web.

BACKGROUND OF THE INVENTION

In a typical paper manufacturing process, a paper web is created on apaper machine and wound onto a large roll called a parent roll. Thepaper web is then unwound from the parent roll and converted intoconsumer sized products on a converting line. In paper manufacturing, asin many manufacturing processes, efficient operations that maximizeoperational time are desired. Defects may occur, however, in the paperweb as it is being manufactured on the paper machine. These defects maybe significant enough to cause the paper web to break while, forexample, the web is being unwound on the converting line. A web breakreduces productivity in the converting line, because an operator muststop the converting line in order to re-thread the paper web. Thisprocess may take from about five minutes to about an hour. At typicalconverting speeds of about two thousand feet per minute, each web breakreduces the amount of paper product produced by about ten thousand feetup to about one hundred twenty thousand feet. It is, therefore,desirable to accurately identify these web defects and take action onthe converting line to prevent web breaks from occurring.

The inspection of a paper web while it is being created on a papermachine is commonly performed in the art. There are also many patents,such as U.S. Pat. No. 6,452,679, directed towards web inspection.Inspection of the paper web on the paper machine is commonly used toprovide real-time feedback for the papermaking process. In this way, thepaper machine can be adjusted to minimize the generation of defects orto adjust other parameters of the paper web, such as basis weight.

The defect information from the web inspection may also be used torepair or to remove the portions of the paper web having the defect,before these portions result in a web break on the converting line or afailure during operation. In U.S. Pat. No. 6,934,028, a paper web isinspected, and defects are classified and located relative toperiodically placed fiduciary indicators. Using these fiduciaryindicators, a portion of the web having a defect may be identified andremoved. Similarly, in U.S. Pat. No. 7,297,969, a paper web isinspected, periodically marked, and wound on a reel. This patentdiscloses a mark sequence in which the spaces between the startingpoints of adjacent marks are used to encode a location along the lengthof the web. These marks may then be used to locate defects on the paperweb that were identified during inspection. The paper web is placed on arepair machine and the reel is unwound. The marks are used to stop theunwinding at a defect location so that the defect may be repaired. Whilenot using a repair machine, U.S. Pat. No. 6,725,123 likewise disclosesusing marks to stop a converting line, so that a defect may be repaired.U.S. Pat. No. 8,060,234 discloses a method and an apparatus similar tothat discussed in U.S. Pat. No. 6,725,123. But, instead of using marksto subsequently identify a location on a paper web on a converting line,U.S. Pat. No. 8,060,234 discloses using an optical signature for onelane of the paper web. The optical signature is the small-scale andlarge-scale variability inherent in a paper web.

In another method known in the art, defects are identified during webinspection and located based on their position relative to one end ofthe paper web. The position of the paper web may be located as afunction of the diameter of a parent roll. A laser may then be used tomeasure the diameter of the parent roll as it is unwound, in order tolocate a defect on the paper web. While the laser may be very precise,small out-of-round conditions on the parent roll may have a large impacton the position of the paper web as measured by the laser. Accordingly,this method has a large uncertainty.

In another method, a web defect is marked with a physical tag, such as atag disclosed in U.S. Pat. No. 5,415,123. This method is heavily relianton operator skill and expertise, because it requires the operator toobserve the tag and to take action to stop the converting line in asufficient amount of time to prevent the defect from causing a web tobreak.

A series of patents, for example, U.S. Pat. No. 7,937,233; U.S. Pat. No.8,175,739; and U.S. Pat. No. 8,238,646, discloses a system in which apaper web is inspected for defects and periodically marked with“fiducial marks.” This system then creates a defect map where defectsidentified during the inspection are mapped relative to the fiducialmarks. These defect maps are then used to apply locating marks at theposition of the defects. Because the paper web is cut into smallersections, a converting plan can be created to more effectively utilizethe paper by cutting around the defects. Further, the defect maps may beused to sort the paper web into different grades of paper.

Each of these methods treats the defects individually and establishesother individual action points to stop and to repair or to discard aportion of the paper web. There is thus a need for improved methods andsystems for defect identification, marking, and converting line control.

SUMMARY OF THE INVENTION

According to one aspect, our invention relates to a system for producinga paper product. The system includes a paper machine for forming a paperweb, an analysis tool, and a converting line for converting the paperweb into a paper product. The paper web produced by the paper machinehas a plurality of sections. The paper machine includes a web analysisunit to perform at least one of inspecting the paper web and identifyingproperties in the paper web. The paper machine also includes a markingunit to mark the paper web with a plurality of marks. At least one markis assigned to each of the plurality of sections. The paper machinefurther includes a winder to wind the paper web into a parent roll. Thewinder is positioned after the web analysis unit and the marking unit.The analysis tool is configured to assign a paper rating to each sectionof the paper web based upon the identified properties in that section ofthe paper web. The converting line has a plurality of operatingparameters. The converting line includes an unwind stand to unwind thepaper web from the parent roll. The converting line also includes a markreading unit that reads at least one of the plurality of marks on thepaper web and produces a corresponding output from the mark that hasbeen read. The converting line further includes a controller thatreceives the output from the mark reading unit and is configured toobtain the paper rating associated with the at least one mark read bythe reading unit and to change at least one operational parameter of theconverting line based upon the paper rating. The converting line yetfurther includes a finisher. The paper web is fed to the finisher andconverted into a paper product.

According to another aspect, our invention relates to a method ofproducing a paper product. The method includes forming a paper webhaving a plurality of sections on a paper machine, and analyzing thepaper web with a web analysis unit to perform at least one of inspectingthe paper web and identifying properties in the paper web. The methodalso includes marking the paper web with a plurality of marks. At leastone mark is marked at each of the plurality of sections. The methodfurther includes winding the paper web with the winder to form a parentroll after the paper web has been inspected and marked. The method stillfurther includes assigning a paper rating to each section of the paperweb based upon the properties in that section of the paper web that areidentified in the analyzing step. The method yet further includesunwinding a paper web from a parent roll on a converting line having aplurality of operational parameters. The method even still furtherincludes reading at least one of the plurality of marks with a markreading unit, obtaining the paper rating associated with the at leastone mark read by the reading unit, and changing at least one operationalparameter of the converting line based upon the paper rating. The methodalso includes converting the paper web into a paper product.

These and other aspects of our invention will become apparent from thefollowing disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a papermaking machine configurationthat can be used in conjunction with our invention.

FIG. 2 is a detailed top plan view of the papermaking machineconfiguration shown in FIG. 1.

FIG. 3 is an exemplary defect database that can be used in conjunctionwith our invention.

FIG. 4 is a defect map of the defect database shown in FIG. 3.

FIG. 5 shows an example of marking that can be used on a paper web inconjunction with our invention.

FIG. 6 shows how the marks of FIG. 5 may be applied to a paper web.

FIG. 7 shows examples of how the paper web may be subdivided.

FIG. 8 shows an example of how the paper web may be analyzed for defectsin conjunction with our invention.

FIGS. 9A through 9C and 9F through 9K are flow charts of steps forassigning inputs for the converting line in accordance with a preferredembodiment of our invention, and FIGS. 9D, 9E, and 9L through 9N showthe development of the scored database.

FIGS. 10A and 10B show a map of the scored database shown in FIG. 9N.

FIG. 11 is a system diagram of an embodiment of our invention.

FIGS. 12A and 12B are schematic diagrams of portions of converting lineconfigurations that can be used in conjunction with our invention.

FIG. 13 shows a control screen for a converting line programmable logiccontroller that can be used in conjunction with our invention.

FIG. 14 is a graph showing an example of a preferred speed profile and anon-preferred speed profile for a converting line.

FIGS. 15A and 15B show an alternate control screen for a converting lineprogrammable logic controller that can be used in conjunction with ourinvention.

FIG. 16 is a flow chart of an embodiment of our invention.

FIG. 17 is a detailed flow chart of process steps at a paper machine forthe embodiment shown in FIG. 16.

FIG. 18 is a detailed flow chart of process steps performed by ananalysis tool for the embodiment shown in FIG. 16.

FIG. 19 is a detailed flow chart of process steps at a converting linefor the embodiment shown in FIG. 16.

FIG. 20 is a flow chart of an alternate embodiment of our invention.

FIG. 21 is a detailed flow chart of process steps performed by ananalysis tool for the embodiment shown in FIG. 20.

FIG. 22 is a detailed flow chart of process steps at a converting linefor the embodiment shown in FIG. 20.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Consumer paper products, such as paper towels, bathroom tissue, and thelike, are made by first creating a paper web on a paper machine. Thispaper web is wound onto large rolls called parent rolls. The parentrolls are then moved to a converting line at which the paper web isunwound from the parent roll and converted into consumer paper products.Our invention relates to methods, systems, and marks for controlling theconverting line.

The term “paper product,” as used herein, encompasses any productincorporating papermaking fibers having cellulose as a majorconstituent. This would include, for example, products marketed as papertowels, toilet paper, and facial tissues. Papermaking fibers includevirgin pulps or recycle (secondary) cellulosic fibers, or fiber mixescomprising cellulosic fibers. Wood fibers include, for example, thoseobtained from deciduous and coniferous trees, including softwood fibers,such as northern and southern softwood kraft fibers, and hardwoodfibers, such as eucalyptus, maple, birch, aspen, or the like. Examplesof other fibers suitable for making the products of our inventioninclude nonwood fibers, such as cotton fibers or cotton derivatives,abaca, kenaf, sabai grass, flax, esparto grass, straw, jute hemp,bagasse, milkweed floss fibers, and pineapple leaf fibers. Furnishrefers to aqueous compositions including papermaking fibers, and,optionally, wet strength resins, debonders, and the like, for makingpaper products.

When describing our invention herein, the terms “machine direction” (MD)and “cross machine direction” (CD) will be used in accordance with theirwell-understood meaning in the art. That is, the MD of a fabric or otherstructure refers to the direction that the structure moves on apapermaking machine in a papermaking process, while CD refers to adirection crossing the MD of the structure. Similarly, when referencingpaper products, the MD of the paper product refers to the direction onthe product that the product moved on the papermaking machine in thepapermaking process, and the CD of the product refers to the directioncrossing the MD of the product.

When describing our invention herein, specific examples of operatingconditions for the paper machine and converting line will be used. Forexample, various speeds will be used when describing paper production onthe paper machine or converting on the converting line. Those skilled inthe art will recognize that our invention is not limited to the specificexamples of the operating conditions, including speed, that aredisclosed herein.

Paper webs may be made on a paper machine implementing any one of anumber of methods known in the art, such as conventional wet pressingand through-air drying. FIG. 1 is a schematic diagram showing anexemplary twin wire wet crepe machine layout that can readily be adaptedto practice our invention. Those skilled in the art will recognize thatother paper machines likewise may be readily adapted to practice ourinvention.

In the paper machine 100 shown in FIG. 1, furnish issues from headbox111 into nip 114 between inner wire 112 and outer wire 113 to formnascent web 101. The nascent web 101 is carried on the inner wire 112and transferred to felt 121, at nip 122. The nascent web 101 is thentransferred from the felt 121 to Yankee cylinder 131 at nip 126 betweensuction pressure roll 123 and the Yankee cylinder 131. In this papermachine 100, felt 121 passes over idler roll 124 before passing aroundblind drilled roll 125 and though nip 127 between the blind drilled roll125 and the Yankee cylinder 131. The Yankee cylinder 131 is a heatedcylinder that is used to dry the nascent web 101. In addition, hot airfrom wet end hood 132 and dry end hood 133 is directed against thenascent web 101 to further dry the nascent web 101 as it is conveyed onthe Yankee cylinder 131. The dried nascent web 101 forms a paper web102. The paper web 102 is removed from the Yankee cylinder 131 with thehelp of doctor blade 134. The paper web 102 is then wound around a reel180 to form a parent roll 190.

Some paper machines create a paper web 102 that is wider than can beused in a subsequent converting process. As a result, the paper web 102may be split into two or more parent rolls 190 using a cutter 160. Therolls may be designated with a letter such as an A roll or a B roll. Thecutter 160 may be a circular blade with a continuous cutting surface.Those skilled in the art will recognize that any suitable cutter may beused including, for example, a water jet cutting system.

In this preferred embodiment, the paper web 102 is inspected for defectson the paper machine 100. As shown in FIGS. 1 and 2, the paper web 102is inspected by web inspection units 141, 142, 143 after the paper web102 leaves the Yankee cylinder 131. The web inspection units are part ofa web inspection system. Those skilled in the art will recognize thatany suitable web inspection systems and units may be used includingthose made by ABB of Zurich, Switzerland; Metso of Helsinki, Finland;Papertec of North Vancouver, BC, Canada; Honeywell of Morristown, N.J.;and Event Capture Systems of Mint Hill, N.C. In the preferredembodiment, each web inspection unit 141, 142, 143 includes at least adigital high speed camera and a light source. The cameras of thepreferred embodiment are set to take images at, for example, one hundredtwenty frames per second and have a resolution of, for example, sixhundred forty pixels by four hundred eighty pixels. The web inspectionunits 141, 142, 143 are positioned a distance above the paper web 102 topreferably have a field of view 150 between about seventy inches andabout one hundred four inches wide, and more preferably, about onehundred two inches wide. An example of a suitable camera includesProsilica GT1910 made by Allied Vision Technologies of Stadtroda,Germany. The web inspection units 141, 142, 143 are also preferablypositioned so the entire width of the paper web 102 is inspected.Preferably, the field of view 150 for each web inspection unit 141, 142,143 has a small amount of overlap of approximately two inches with thefield of view 150 of the adjacent web inspection unit 141, 142, 143. Theresolution and distance from the paper web determine the size of anindication or a defect that can be detected. Increasing the resolutionof the camera will enable smaller defects to be detected. Alternatively,placing the camera closer to the paper web enables smaller defects to bedetected, but the field of view is also decreased and more cameras willbe needed to image the entire width of the paper web 102. The lightsource is preferably an array of light emitting diodes used toilluminate the paper web 102. In the preferred embodiment, the lightsource is positioned coincident with the camera. Those skilled in theart will recognize that any suitable light source may be used, includinghigh frequency florescent lighting or halogen lighting. The light sourcemay also be positioned elsewhere on the paper machine 100 includingbelow the paper web 102. As those skilled in the art will recognize, thelighting requirements will depend upon the camera settings, includingframe rate and aperture.

Any suitable web inspection system that is capable of analyzing thecaptured images to identify and to classify defects may be used.Further, any suitable method of identifying and classifying defects maybe used, such as gray scale analysis or image comparison. In thepreferred embodiment, defects are identified by using a gray scalemethod. The paper web 102 appears white to the camera, because the paperweb 102 reflects the light from the light source. Defects, on the otherhand, are non-reflective and appear dark to the camera. The opposite,where the paper web 102 appears dark to the camera and defects appearwhite, occurs when the lighting is positioned below the paper web.Defects may thus be identified as pixels in the images captured by webinspection units having a gray scale value darker than a predeterminedthreshold. Once identified, the dimensions and positions of individualdefects may be determined. The defect analysis method discussed in U.S.Patent Appln. Pub. No. 2012/0147177, which issued as U.S. Pat. No.9,172,916, (the disclosure of which is incorporated by reference in itsentirety) may be used to distinguish between true defects and falsepositives. Many different types of defects may be identified by the webinspection system. In the preferred embodiment, the web inspection units141, 142, 143 identify holes, tears, wrinkles, chemical coating streaks,and the like.

When the defects are identified by the web inspection system, they arepreferably recorded in a table or a database, such as the table shown inFIG. 3. A “database,” as used herein, means a collection of dataorganized in such a way that a computer program may quickly selectdesired pieces of the data. An example is an electronic filing system.In the preferred embodiment, the time the defect is detected, thelocation of the defect, and defect specific information are recorded ina database. This database may be referred to as the defect database, andin the preferred embodiment, all data is established in the databasewith respect to a master time reference. As an example, the leading edgeof the paper web 102 in the machine direction passes the web inspectionunits 141, 142, 143 at 09:34:01. The first web defect is identified at09:41:10, which is recorded in the defect database. The first defect islocated one thousand feet in the machine direction (MD) from the leadingedge of the paper web 102 and ten inches from one of the edges of thepaper web 102 in the cross-machine direction (CD). By grayscaleanalysis, the first web defect is identified as having both a length anda width of one half inch, resulting in an aspect ratio of length towidth of one. Similarly, the second web defect is recorded at 10:10:00and has an aspect ratio of 0.0625. Defects may be classified by theaspect ratio. In this case, the first web defect is considered to be ahole and the second web defect is considered to be a tear. This processis then repeated for the entire parent roll. The defects may also berepresented graphically in a defect map such as the map shown in FIG. 4.Here, the first web defect is shown with an open circle in the upperleft of the paper web 102. The second web defect is similarly shown withan open triangle.

The defect database may be stored in a non-transitory computer-readablemedium in order to facilitate the analysis described below. Anon-transitory computer readable medium, as used herein, comprises allcomputer-readable media except for a transitory, propagating signal.Examples of non-transitory computer readable media include, for example,a hard disk drive and/or a removable storage drive, representing a diskdrive, a magnetic tape drive, an optical disk drive, etc. Thenon-transitory computer readable media may be connected to processors,programmable logic controllers for converting line control, the webinspection system using network connections that are common in the art,and other controllers and systems used in our invention. When thenon-transitory computer readable media is connected to a network, it maybe referred to as a file server.

Other paper web properties may be measured on the paper machine 100, forexample, moisture content and basis weight of the paper web. In thisembodiment, as shown in FIG. 1, a web property scanner 155 is positionedafter the Yankee cylinder 131 and before web inspection units 141, 142,143. Any suitable web property scanner 155 known in the art may be usedto measure web properties. An example of a suitable web property scanner155 is an MXProLine scanner manufactured by Honeywell of Morristown,N.J., that is used to measure the moisture content with beta radiationand basis weight with gamma radiation. As these data are collected, theweb property is recorded in a database along with the time that theproperty was obtained. This database may be the defect database or aseparate database for web properties (e.g., web properties database). Inaddition, web properties may also be indirectly determined from otheroperating parameters of the paper machine 100. Operating parameters suchas pump speeds, fan speeds, and the like, may be correlated to webproperties. By monitoring and recording these operating parameters, webproperties can be calculated and recorded in the web propertiesdatabase.

In order to effectively utilize the defect information generated duringweb inspection, the paper web 102 is marked at a set periodicity withmark 210. As shown in FIGS. 1 and 2, the paper web 102 is preferablymarked after the web inspection units 141, 142, 143 and prior to beingwound on the reel 180. In the preferred embodiment, marking units 171,172 are positioned adjacent to the cutter 160. This position allows foraccurate and repeatable application of mark 210. Cutting the paper web102 requires that the paper web 102 be stable when it is cut,particularly, that the paper web 102 is taut and moved at a constantspeed. Both of these conditions are well suited for accurate applicationof mark 210. Further, the outside edges of the paper web 102 may move inthe cross-machine (CD) direction when viewing a particular point on thepaper machine 100, because either the width of the paper web 102 changesor the paper web 102 as a whole shifts. By applying mark 210 near thecutter 160, the mark 210 can be positioned at a set distance from anedge of the paper web 102, making reading the mark 210 easier on theconverting line and ensuring that the mark 210 is removed when thefinished product is cut to length. The MD distance between the webinspection units 141, 142, 143 and the marking units 171, 172 is alsopreferably minimized. As with the defects, the mark 210 is recorded inthe defect database according to a master time reference. Preferably,the same time should correspond to the same MD location on the paper. Ifthe web inspection units 141, 142, 143 and the marking units 171, 172are separated, however, a correction factor would need to be applied toone of the time references. This introduces a source of uncertainty.

Any suitable marking unit 171, 172 may be used, such as COM-2112manufactured by Ryeco Inc. of Marietta, Ga. Also, any suitable ink maybe used to mark the web, including food grade ink or ink that is visibleunder ultraviolet light. Ink that may be detected under ultravioletlight is advantageous in the event that the mark is not properly removedduring the converting process. In this case, the mark is not visible toa consumer, even though the mark remains on the consumer product.

The mark of the preferred embodiment is a binary mark made of multiplediscrete positions over a set distance of the paper web 102. As shown inFIG. 5, the mark includes N positions. Each position is either blank,indicating a value of zero, or contains ink, indicating a value of one.Ideally, the mark length 630 (see FIG. 6) is as small as possible andcould be a bar code. Such a mark could be used to practice ourinvention, but the marking technology, especially for paper making usedfor tissue and towel, has not yet advanced to make such marks practical.Ink marks have a tendency to spread on the paper web. Thus, it isdifficult to precisely control the width of the ink mark as is necessaryfor a bar code. Additionally, at typical reel speeds of about threethousand five hundred feet per minute, the length of any mark will belimited by the rate of discharge from an ink head. We have thus foundthat the ink is preferably applied as a dash that is about onethirty-second of an inch in width and about three inches in length. Attypical reel speeds, the marking unit 171, 172 discharges ink for abouttwo milliseconds to create a mark of three inches in length. Further, adash provides a sufficient time for the mark to be detected and read ona converting line. (The converting line speeds may range from about onethousand three hundred feet per minute to about three thousand feet perminute.) A position is preferably less than about twenty inches inlength, more preferably, less than about six inches in length, and, mostpreferably, about three inches in length. The start of each position issimilarly preferably separated from adjacent positions by about twentyinches or less, more preferably, about six inches or less, and, mostpreferably, about three inches. Those skilled in the art will recognize,however, that other types of ink applications, including dots, may beused without deviating from the scope of our invention. The markpreferably contains between about sixteen positions and aboutsixty-eight positions, and, more preferably, about thirty-eightpositions. The number of positions in a mark is a balance betweenproviding enough positions or bits to convey the information containedin the mark and keeping the mark to a reasonable length. A mark asdescribed above with thirty-eight positions will preferably have a marklength 630, as shown in FIG. 6, of about sixteen feet.

In the preferred embodiment, the first two positions (positions one andtwo in FIG. 5) each contains a dash. Together, the two dashes indicatethe start of a mark. Similarly, the last two positions (positions N−1and N in FIG. 5) will contain a dash to indicate the end of the mark. Inreading the mark, a mark reading unit (discussed below) can distinguishbetween marks when a predetermined amount of time has passed betweensuccessive detections of ink. This predetermined amount of time shouldbe longer than the time it takes for the mark to pass by the readingunit.

The remaining thirty-four positions in the preferred embodiment are usedto identify the parent roll and the lineal position of the mark on theparent roll. Positions three to five may be used to identify theparticular paper machine and the mill from which the roll originated,positions six and seven may be used to identify whether the roll is an Aroll or a B roll (as discussed above). Positions eight to twenty-fourmay be used to identify the specific roll. These positions may also beused to establish an inventory. In the present embodiment, the inventorynumbers in positions eight to twenty-four are used on a rotating basis.A number is assigned to a parent roll when it is created. Once theparent roll is converted or otherwise used, the number may then beassigned to another parent roll. Taken together, positions three totwenty-four may be referred to as roll identification information or theparent roll identification number. The remaining positions, twenty-fiveto thirty-six may be used to convey a particular location with the paperweb 102 and may be referred to as location information, linear footage,or MD footage, for example. When these thirty-eight positions areinsufficient to convey this information in a single mark, additionalpositions may be added to the mark. As used hereafter, the foregoingwill be referred to as the single mark embodiment where mark 610 andmark 620 shown in FIG. 7 are the same.

Alternatively, two marks can be used. One mark can be a rollidentification mark 610 and a second mark can be a location mark 620.Those skilled in the art will recognize that any number of marks may beused to convey the desired information from the paper machine to theconverting line. As used hereafter, this type of marking configurationwill be referred to as the multi-mark embodiment. In the rollidentification mark 610, for example, the positions may be used toidentify the particular paper machine and the mill from which the rolloriginated, used to identify whether the roll is an A roll or a B roll(as discussed above), and used to establish an inventory. In thelocation mark 620, the positions may be used to convey a particularlocation within the paper web 102.

In the preferred embodiment shown in FIG. 6, marks 610 and 620 areapplied to the paper web 102 at a set periodicity. The marks are spacedsuch that the distance between the start of adjacent marks 631 is apredetermined distance. In the single mark embodiment, the distancebetween adjacent marks 631 is the distance of control on the convertingline. This distance is thus set as a result of many factors includingthe speed of the converting line, the ability of the mark reading unitto distinguish between adjacent marks, a goal of minimizing the amountof product recycled, and the like. As will be discussed in more detailbelow, the distance between adjacent marks 631 may also determine thedistance over which the paper web 102 is analyzed to develop convertingline control inputs. Closer marks thus result in a finer analysisinterval, and a more precise increment for control of the convertingline. In addition, more frequent marks reduce the opportunity for erroron the converting line. We have found that the distance between adjacentmarks 631 is preferably between about two hundred fifty feet and aboutone thousand feet, and, more preferably, about four hundred feet. In themulti-mark embodiment, successive marks alternate between a rollidentification mark 610 and a location mark 620. When two marks areused, the distance between marks of the same type 632 is a predetermineddistance. This distance 632 sets the distance of control on theconverting line for the multi-mark embodiment. We have found that thedistance between marks of the same type 632 is preferably between aboutthree hundred feet and about one thousand feet, and, more preferably,about five hundred feet. We have found that, in the multi-markembodiment, the distance between adjacent marks 631 is preferably halfthe distance between marks of the same type 632. In either embodiment,the mark and the time that the mark is applied are recorded in thedefect database when a mark 610 or 620 is applied to paper web 102.

Once the defects have been identified and recorded in the defectdatabase, they are then analyzed to develop inputs for converting linecontrol. In the preferred embodiment, this analysis is performed usingan analysis tool. Additional information beyond that recorded in thedefect database may be useful in establishing converting line controlinputs. A consolidated database is thus created by adding thisadditional information to the defect database. Those skilled in the artwill recognize that this additional information includes commonlymeasured properties of the paper web, such as the moisture content ofthe paper web, the basis weight of the paper web, the tensile strengthof the paper web, and the like. This additional information may includethe information stored in the web properties database, discussed above.While the moisture content of the paper web and the basis weight of thepaper web may be collected directly on the paper machine 100 (asdiscussed above), these data may also be collected offline and includedin the analysis as an input into the consolidated database. In thefollowing discussion, the moisture content and basis weight will bediscussed in the context of collecting these data offline. Thisadditional information may be entered into the consolidated database asa constant value for the entire parent roll or may vary depending uponthe location in the parent roll. As with the defect database, if thepaper web properties vary along the length of the paper web, theproperties are entered using a master time reference. Additionally,other paper web problems, such as a paper web break, may not beautomatically included in the defect database from the web inspectionsystem. Locations of web breaks are then input into the consolidateddatabase according to the time of occurrence. In addition, parent rolls190 may be assigned a so-called “TAPPI Roll Number,” which is a numberused to identify parent rolls 190 and assigned according to TechnicalAssociation of the Pulp and Paper Industry (TAPPI) Technical InformationPaper (TIP) 1004-01. The TAPPI Roll Number may also be added to theconsolidated database.

Once a consolidated database has been established, the analysis toolthen analyzes the consolidated database to develop inputs for convertingline control. The objective of the analysis is to generate an output fora specific portion of the web. This portion may be called a block. Inthe preferred embodiment, each block is associated with the markcontaining the linear footage of the parent roll 190 (both marks 610 and620 in the single mark embodiment and location mark 620 in themulti-mark embodiment). Those skilled in the art will recognize that thepaper web 102 may be separated into blocks and associated with alocation mark in a number of different ways. As shown in FIG. 7, forexample, block 711 may extend from the center of one roll identificationmark 610 to the center of the next roll identification mark 610. In thisway, block 711 is centered about a location mark 620. Alternatively,block 712 may extend from the beginning of location mark 620 to thebeginning of the next location mark 620. Blocks 711, 712 may be furthersubdivided into segments 720. As shown in FIG. 7, each block 711, 712 issubdivided into four equal segments 720.

Inputs for converting line control are developed for each block 712 bydetermining the likelihood of converting line failure for each block712. Those skilled in the art will recognize that converting linefailure refers to a number of different problems that could occur on aconverting line. Such problems include the paper web breaking, the paperweb wrapping on a roller, and the like. While some web defects and outof specification paper web properties are unlikely to cause convertingline failure, these defects or properties may, nonetheless, beundesirable in a consumer product. Such defects or properties are oftenreferred to as quality defects. Inputs for converting line control mayalso be developed for each block 712 to prevent these quality defectsfrom being converted into consumer products. Any suitable inputs may beused, but we will discuss two approaches. The first approach, used inthe preferred embodiment, is to use two criteria, an action score and aquality score, for converting line control. The first criterion is anaction score and is established based on the likelihood of convertingline failure. The action score may consist of three values: zero, one,or two. An action score of zero indicates a low likelihood of convertingline failure. The converting line will not take any action for blocks712 of the paper web with a score of zero. An action score of oneindicates a high likelihood of converting failure with the mostappropriate action being not converting that block 712 of the paper web.In this case, the converting line will be stopped to remove the block712 with an action score of one and/or the converting line will spliceto another parent roll 192 (FIG. 12A). An action score of two indicatesa moderate likelihood of converting line failure. Here, the block 712may be converted, but the converting line takes a mitigating action,such as slowing, reducing tension, and the like, to mitigate the risk ofconverting line failure.

The second criterion is a quality score and is established based on theneed to reject a section of the paper web to prevent unacceptablequality defects. The quality score may consist of two values: zero orone. A quality score of zero indicates that there are no identifiedquality defects in block 712 of the paper web. A quality score of oneindicates a quality defect that is unacceptable for delivery toconsumers and that block 712 should be removed from further processing.For example, when the converting line is preparing rolled paper product(such as paper towels), a log 1080 (FIG. 12A) may be removed after it isformed and before it is further processed in the log saw 1094 (FIG.12A).

The second, alternative approach of inputs for converting line controlis a fault code and severity level. Fault codes may be, for example, atype of converting line failure or converting line problem, such asbreak, wrap, quality, and the like. Those skilled in the art willrecognize that any number of suitable criteria may be used. The severitylevel may be a numerical value between, for example, one and ten, withten being the most severe. A zero value for a severity level mayindicate that a fault is unlikely.

The process of assigning the fault code and the severity level or theaction score and the quality score will now be described. We have foundthat with either type of input (fault code and severity level or actionscore and quality score), a layered or multi-pass analysis approach ispreferred. In this approach, the consolidated database is analyzed forone type of defect or defect grouping before moving on to the nextdefect type. A benefit of the layered or multi-pass analysis approach isthat each layer or pass is independent of another. In this way, it iseasy to modify the analysis for one particular defect type without themodification impacting the other defect passes. Similarly, it is easy toadd or to delete different analysis passes without modifying the otherpasses. The analyses discussed below may be performed over any suitableanalysis window 730, which may include, for example, a single block 712or multiple blocks 712 as shown in FIG. 8. One having ordinary skill inthe art will recognize, however, that our invention is not limited tothe following methods of assigning inputs for converting line control.Rather, those skilled in the art will recognize that a number ofdifferent approaches may be taken to assign the inputs for convertingline control without departing from the scope of our invention.

We will now describe the process for assigning an action score and aquality score with reference to FIGS. 9A to 9N and FIGS. 10A and 10B(with periodic reference to FIGS. 1 and 8). The process overview isshown in FIG. 9A. Each block 712 begins the analysis with a defaultaction score and a quality score of zero. In step S800, a break analysisis performed for each block 712 in the parent roll 190. If the analysisdetermines that a block 712 has a high likelihood of the paper web 102breaking on the converting line, the action score will be set to one forthat block 712 and the action footage will be set to the next markstarting footage (as will be discussed further below). For any blocks712 in the parent roll 190 not having an action score set to one, a slowanalysis is performed in step S810. Here, if the analysis determinesthat a block 712 has a moderate likelihood of the paper web 102 breakingon the converting line, the action score will be set to two and theaction footage will be set to the next mark starting footage. The blocks712 are then analyzed for quality defects in step S820. If any qualitydefects are identified, the quality score will be set to one. Theanalysis is then completed in step S830.

FIG. 9B shows the analyses performed as part of the break analysis S800.First, each block 712 is checked for any marked breaks from the papermachine 100, in step S840. If a break has been marked for a block 712,the action score is set to one for that block 712 and the action footageis set to the next mark starting footage. For the blocks that do nothave an action score set to one, the break analysis then proceeds to thenext step S850 to check the sheet attributes. The process is thenrepeated for each of the remaining four analyses S860, S870, S880, andS890. Once all of these analyses has been performed, the break analysisS800 is then completed in step S831. We will now describe each of theseanalyses in turn.

FIG. 9C is a detailed flow chart of the analysis for marked breaks S840.FIG. 9D is an example of a consolidated database before analysis, andFIG. 9E is the consolidated database after the marked breaks analysisS840 has been performed. First, in step S841, the current block 712 ischecked to identify if any break signals have been recorded. As shown inFIG. 9D, a break signal has been recorded for the fifth mark with alinear footage of two thousand one hundred seventy-five feet. For thisbreak, the action score is set to one in step S842 and the actionfootage is set to the next mark footage (in this case, mark six at twothousand four hundred feet) in step S843. Then, the analysis proceeds tostep S844 where it determined if this block 712 is the end of the roll.If so, the next analysis is started in step S845. If not, the process isrepeated for the next block 712. When no break signal is recorded, nochange is made to the action score and action footage, and the analysisproceeds to step S844.

As discussed above, the linear footage is measured from the leading edgeof the parent roll 190. This edge, however, is the last portion to beconverted on the converting line because converting begins at the end ofthe parent roll 190. For this reason, each action analysis sets theaction footage as the next mark footage and not the footage associatedwith the current block 712. As shown in FIGS. 10A and 10B, for example,the paper web 102 will be converted from left to right. Although theblock associated with the fifth mark contains a web break, the web breakwould have already caused a converting line failure if the action scoreof one and action footage of one thousand eight hundred feet was notprocessed until the fifth mark was read. As a result, the sixth mark,which has an action footage of two thousand four hundred feet, is set toindicate the upcoming web break and not action footage one thousandeight hundred feet, which is associated with the fifth mark.

FIG. 9F is a detailed flow chart of the check sheet attributes analysisS850. First, the sheet attribute data for the current block 712 isobtained in step S851. Sheet attribute data may also be referred to asweb properties and includes any aspect of the web that is not visible tothe naked eye. Specific examples include those properties discussedabove, such as basis weight, moisture content, and MD tensile strength.Each attribute being analyzed for the likelihood of failure is comparedto a threshold value in step S852. Typically, each attribute has atarget mean and a variance of the attribute for the current block 712can be calculated compared to that mean. If the variance exceeds a breaklimit, the action score will be set to one in step S853 and the actionfootage set to the next mark footage in step S854. The analysis thenproceeds to steps S855 and S856, which are similar to steps S844 andS845, respectively. If the variance is less than or equal to the breaklimit, no change to the action score will be made, and the analysis willproceed to steps S855 and S856. Different types of paper product will beconverted differently and respond to a converting line differently.Compare, for example, tissue product to towel product. Even within atype of product, there are different grades, for example, towel productproduced for commercial use compared to towel product produced forconsumer use. The break limit for each attribute is thus set differentlyfor different grades of product. Additionally, converting lines used toconvert the same product may have differences, and thus, the break limitfor each attribute may be customized for each different asset.

FIG. 9G is a detailed flow chart of the check defect and sheetattributes analysis S860. Even though the individual variance of anattribute did not exceed the break limit, some variances when combinedwith a defect could lead to a high likelihood of converting linefailure. Both sheet attribute data for the current block 712 and thedefect data for the record being analyzed are obtained in step S861. Asshown in FIG. 9L and as discussed above, each defect is recorded in theconsolidated database as its own record. For example, a small hole isrecorded as data table entry number two. Then, the attribute data iscompared to a break limit in step S862, similar to the comparisonperformed in step S852, but for a lower break limit. If the varianceexceeds the break limit, the defect data is compared against a breaklimit. In this example, it is the size of the defect that is evaluated,but those skilled in the art will recognize that other defect criteriamay also be evaluated, including those discussed below in conjunctionwith steps S870, S880, and S890. If the size of the defect exceeds thebreak limit, then the action score is set to one in step S864 and thefootage is set to the next mark footage in step S865. The analysis thenproceeds to steps S866 and S867, which are similar to steps S844 andS845, respectively, but before proceeding to the next block 712, eachdefect within the current block is analyzed. If either of the breaklimits is not exceeded, no action score is set and the analysis proceedsto steps S866 and S867.

FIG. 9H is a detailed flow chart of the check edge defect analysis S870.A defect on the edge of the paper web will generally have a greaterlikelihood of resulting in a converting line failure than the samedefect located toward the center of the sheet. Thus, a defect record,for the current block 712, having a position near the edge of the paperweb is identified in step S871. In this embodiment, edge defects arethose having a CD position located within the first five percent or thelast five percent of the CD width (i.e., CD position is less than fivepercent or greater than ninety-five percent). Once the defects areidentified, they are then compared to the break limit is step S872. Ifthe size of the defect exceeds the break limit, then the action score isset to one in step S873 and the footage is set to the next mark footagein step S874. The analysis then proceeds to steps S875 and S876, whichare similar to steps S866 and S867, respectively. If the break limit isnot exceeded, no action score is set and the analysis proceeds to stepsS875 and S876.

FIG. 9I is a detailed flow chart of the check single defect analysisS880. This analysis assesses the likelihood of converting line failurefor a single defect. Here, a defect record for the current block 712having a size greater than a limit is identified in step S881. The sizeis then compared to the break limit in S882. If the size exceeds thebreak limit, then the action score is set to one in step S883 and thefootage is set to the next mark footage in step S884. The analysis thenproceeds to steps S885 and S886, which are similar to steps S866 andS867, respectively. If the break limit is not exceeded, no action scoreis set and the analysis proceeds to steps S885 and S886.

FIG. 9J is a detailed flow chart of the check cluster defect analysisS890. This analysis assesses the likelihood of converting line failureof a combination or cluster of defects. Here, a defect record (currentrecord) for the current block 712 is obtained in step S891. Then, thedefect data for records located within a certain distance of the currentrecord (for example, within plus or minus thirty feet in the MDdirection) are obtained in step S892. The density of the positions ofthese defects is compared to a break limit in step S893. If the densityexceeds the break limit, then the action score is set to one in stepS894 and the footage is set to the next mark footage in step S895. Theanalysis then proceeds to steps S896 and S897, which are similar tosteps S866 and S867, respectively. If the break limit is not exceeded,no action score is set and the analysis proceeds to steps S896 and S897.

Once the break analysis is completed, the slow analysis is performed instep S810. FIG. 9K shows the analyses performed as part of the slowanalysis. Each of the analyses S811, S812, S813, S814, and S815 isperformed in a similar way as the corresponding break analysis, S850,S860, S870, S880, and S890, respectively. The limits for the slowanalyses, however, are lower than the limits for the break analyses. Thequality analyses S820 are also performed in a like manner.

FIG. 9L shows an example of a consolidated database prior to performingbreak analysis S800. FIG. 9M shows the consolidated database afterperforming break analysis S800. The defect records in the first markcorrespond to a cluster of defects. The defect record in the third markcorresponds to an edge defect. The defect record in the fourth markcorresponds to a large defect. The data table entry fourteen correspondsto a web break signal as discussed above with reference to FIGS. 9D and9E. The sixth mark has a low basis weight, and the seventh mark has acombination of a low basis weight and a defect. As will be discussedfurther below, the action score and the footage for the next block witha non-zero action score is sent for each mark to the converting linecontroller. Once the action score and quality score have been assignedfor each block 712, the remaining marks are then updated to have theaction score and action footage of block 712 with the next non-zeroaction score to result in the scored database. This database is shown inFIG. 9N. (FIGS. 10A and 10B are graphical illustrations of thisdatabase, similar to that shown in FIG. 4.)

We will now describe an alternative approach of inputs for convertingline control using fault codes and severity levels, with reference backto FIG. 8. Because the likelihood of failure in one segment may beinfluenced by an adjacent segment, the likelihood of failure isdetermined over an analysis window 730. An analysis window 730 could be,for example, an individual block. In the preferred embodiment, theanalysis window 730 encompasses multiple blocks 712. In this example, ananalysis is being performed to assign fault codes and severity levelsfor the block 712 corresponding to analysis centerline 740. Anadditional advantage of an analysis window that encompasses multipleblocks is that some degree of smoothing can occur. As will be discussedfurther below, it is preferable to ramp down or to ramp up convertingline parameters, instead of making sudden changes.

Then, for defects corresponding to one of the fault codes, a severitylevel may be established as a composite score from each of the analysispasses. For example, each block 712 of the consolidated database may bereviewed for a recorded web break that occurred on the paper machine 100(FIG. 1). This type of defect is associated with a break fault code andeach of the blocks 712 having this defect would be assigned a fault codeof break with a severity level of ten. Next, each block 712 of theconsolidated database may be reviewed for tears. Each block 712 having atear would be assigned the fault code break with a severity levelcorresponding to the length of the tear. At a next pass, each segment720 may be reviewed to determine if the number of defects or total sizeexceeds a threshold value. Various threshold values could be used, eachcorresponding to a different severity level for break fault codes. Thenext pass could expand the analysis window 730 to encompass adjacentblocks 712. Within the analysis window, a fault code of break could beassigned with a severity level when adjacent segments 720 contain atotal number or total size of defects exceeding a threshold value.Again, various threshold values could be used, each corresponding to adifferent severity level for break fault codes. Once all of the analysispasses for defects to be assigned a break fault code are completed, acomposite severity can be calculated when a block has been assigned twoor more severity levels from the analysis passes.

The analysis process and severity level assignment may be modified bytaking into account other web properties. For example, when a block 712or, a segment 720 has a low basis weight, low tensile strength, or highmoisture content, the severity level may be increased for that block712. The process may then be repeated for other fault codes, such aswrap and quality.

The foregoing methods and processes for assigning inputs for convertingline control by the analysis tool 912 may be implemented on a computer.A system diagram showing how the analysis tool 912 is interconnected tothe paper machine and the converting line is depicted in FIG. 11. Asdiscussed above (see FIGS. 1 and 2), the web inspection system, webmarking unit 171, 172, and web property scanner 155 populate the defectdatabase. The web inspection system may include web inspection units141, 142, 143 connected to web inspection computer 902. Likewise, theweb marking unit 171, 172 and the web property scanner 155 may also beconnected to a web marking computer 904 and a web property computer 906,respectively. These three computers 902, 904, 906 are configured toprocess the inspection, marking, and property data, and then transmitthe data to a database server 910 to populate the defect database.Additional web information that is collected offline may be added to thedefect database to create the consolidated database through an offlineinput personal computer (PC) 908. The consolidated database may also bestored on the database server 910. The analysis tool 912 then retrievesthe consolidated database from the database server to create the inputsfor the converting line. As depicted in FIG. 11, the analysis tool 912is its own computer, but alternatively, the analysis tool 912 may beimplemented on the database server 910. Once the analysis is completed,the scored database is transmitted to a roll server 914 and stored onthe roll server 914. The roll server 914 may also be implemented on thesame server as the analysis tool 912 or database server 910. Upon thestart of converting, a master converting line computer 920 retrieves thescored database from the roll server 914 to use in the convertingprocess, which will be discussed further below. In this regard, we willdiscuss that the converting line retrieves the scored database byidentifying a marked edge of the paper web 102.

The procedures depicted and discussed above with reference to the papermachine, offline input PC, database server, analysis tool, analysistool, or any portion or function thereof, may be implemented by usinghardware, software, or a combination of the two. Likewise, theprocedures depicted and discussed below with reference to the convertingline, or any portion or function thereof, may be implemented by usinghardware, software, or a combination of the two. The implementation maybe in one or more computers or other processing systems. Whilemanipulations performed in these embodiments may have been referred toin terms commonly associated with mental operations performed by a humanoperator, no human operator is needed to perform any of the operationsdescribed herein. In other words, the operations may be completelyimplemented with machine operations. Useful machines for performing theoperation of the embodiments presented herein include general purposedigital computers or similar devices.

Portions of the embodiments of the invention may be convenientlyimplemented by using a conventional general purpose computer, aspecialized digital computer, and/or a microprocessor programmedaccording to the teachings of the present disclosure, as is apparent tothose skilled in the computer art. Appropriate software coding mayreadily be prepared by skilled programmers based on the teachings of thepresent disclosure.

Some embodiments include a computer program product. The computerprogram product may be a non-transitory storage medium or media havinginstructions stored thereon or therein that can be used to control, orto cause, a computer to perform any of the procedures of the embodimentsof the invention. As discussed above, the storage medium may include,without limitation, a floppy disk, a mini disk, an optical disc, aBlu-ray Disc, a DVD, a CD or CD-ROM, a micro drive, a magneto-opticaldisk, a ROM, a RAM, an EPROM, an EEPROM, a DRAM, a VRAM, a flash memory,a flash card, a magnetic card, an optical card, nanosystems, a molecularmemory integrated circuit, a RAID, remote datastorage/archive/warehousing, and/or any other type of device suitablefor storing instructions and/or data.

Stored on any one of the non-transitory computer readable medium ormedia, some implementations include software for controlling both thehardware of the general and/or special computer or microprocessor, andfor enabling the computer or microprocessor to interact with a humanuser or other mechanism utilizing the results of the embodiments of theinvention. Such software may include, without limitation, devicedrivers, operating systems, and user applications. Ultimately, suchcomputer readable media further includes software for performing aspectsof the invention, as described above.

Included in the programming and/or software of the general and/orspecial purpose computer or microprocessor are software modules forimplementing the procedures described above.

Next, we will describe a converting line and control of the convertingline for a preferred embodiment of our invention, with reference toFIGS. 12A to 14B. Parent rolls 190 (191, 192 in FIGS. 12A and 12B) areconverted to consumer sized rolls and other products at a convertingline. Our invention may be adapted to work with any number of differentconverting lines known in the art. One of the simplest forms ofconverting lines is for a single-ply paper towel product. Here, a paperweb is unwound from a parent roll 191, 192 at an unwind stand 1010 andthen rewound into a log 1080 at a rewinder 1076. A log 1080 is the widthof a parent roll, but has the diameter of the consumer sized product.Also, at the rewinder 1076, the outermost end of paper web is glued by atail gluer when the end is cut from the paper web feeding the rewinder.The log 1080 is subsequently cut into consumer length products using alog saw 1094. Those skilled in the art will recognize that a convertingline may encompass more operations than described above. For example,the paper web may be embossed by passing through a nip defined between,for example, an embossing roller 1072 and an anvil roller 1074. Further,the paper web from two or more different parent rolls 191, 192 may becombined prior to being wound into a log 1080 in order to form amulti-ply sheet. Other converting lines may not create rolls of consumerproducts, but instead, cut the web after embossing to form flat productssuch as napkins, facial tissue, and the like. These types of convertinglines use a folder 1078 instead of a rewinder 1076. In this application,we will use the term finisher to generically refer to a rewinder 1076, afolder 1078, and the like. Even among converting lines established tomake the same product, the equipment may differ. For example, someunwind stands 1010 may hold a single parent roll 191, 192, but othersmay hold two parent rolls 191, 192 and have the capability to switchbetween parent rolls 191, 192 without stopping the converting line.Switching between parent rolls 191, 192 may be accomplished through theuse of a flying splice, as is known in the art, and will be discussed inmore detail below. FIGS. 12A and 12B show schematic diagrams of anexemplary unwind stand 1010 having a flying splice.

FIG. 12A, thus, is a schematic diagram of an exemplary unwind stand 1010and rewinder 1076. Parent rolls 191, 192 are placed on each of the rollmounts 1011, 1012. Each parent roll is driven by a motor 1013, 1014 thatis connected to the parent roll 191, 192 through the use of drive belts1015, 1016. The paper web 102 is being drawn from parent roll 191 andrewound in rewinder 1076 to create log 1080. The paper web 102 isconveyed over a series of rollers 1041, 1043, 1045, 1046, and 1050between parent roll 191 and rewinder 1076. The depicted unwind stand1010 is capable of performing a flying splice to switch from parent roll191 to parent roll 192. To perform a flying splice, parent roll 192 isbrought up to the speed of parent roll 191 by motor 1014. While theparent roll 192 is being brought up to speed, paper web 103 is beingrewound on recovery roll 1022. (Recovery roll 1021 is used in the sameway as recovery roll 1022 when switching from parent roll 192 to parentroll 191.) When splicing between parent rolls, press rollers 1031, 1032bring paper web 102 together with paper web 103, and cutters 1033, 1034are used to sever the paper web 103 from the recovery roll 1022 andpaper web 102 from the rewinder 1076. Once the paper web 103 for log1080 is being drawn from parent roll 192, parent roll 191 may bereplaced with another parent roll or a portion of the paper web 102having a defect may be removed. In the converting line depicted in FIG.12A, the paper web 102 is embossed as it travels through a nip formedbetween and embossing roller 1072 and an anvil roller 1074. After beingwound into a log 1080, the log is transferred to an accumulator 1092before being cut into consumer sized lengths by a log saw 1094. Theconsumer size products are then packaged for distribution and sale bysubsequent packaging equipment 1090.

FIG. 12B is a schematic diagram of another exemplary converting line.This converting line is similar in operation to the converting linedepicted in FIG. 12A, but includes a folder 1078 to produce foldedconsumer products such as napkins, tissues, and the like, instead of arewinder 1076.

Converting lines are conventionally classified into class one and classtwo converting lines. Class one converting lines typically operate at aspeed of about two thousand feet per minute for bath tissue and abouttwo thousand seven hundred feet per minute to about three thousand feetper minute for towel products. Class two converting lines typicallyoperate in the range of about one thousand three hundred feet per minuteto about one thousand seven hundred feet per minute for all products.

In the preferred embodiment, the converting line 1000 is controlledthrough the use of a programmable logic controller (PLC) 924 (FIG. 11).In the discussion below, we will discuss the automated control of theconverting line by referencing adjusting the converting line speed,splicing between parent rolls, and stopping the converting line. Thoseskilled in the art will recognize, however, that there are numerousparameters that can be controlled by the PLC 924 on the converting line,including tension between rollers and nip parameters, such as a gapbetween the rollers comprising the nip. Our invention may be readilyadapted to control any number of these parameters, either individuallyor in concert with the other parameters.

In the embodiment shown in FIGS. 12A and 12B (with periodic reference toFIGS. 6, 7 and 11), a mark reading unit 1060 is positioned shortly afterthe location where the paper web 102 is unwound from parent roll 191.The mark reading unit 1060 is positioned to inspect the edge of theparent roll 191 and to read any mark 610, 620 that passes. In thepreferred embodiment, the mark reading unit 1060 includes at least adigital high speed camera to read the mark and a light to illuminate theedge of the paper web 102. Any suitable high speed camera may be used inthe mark reading unit 1060. Further, any suitable light source may beused, such as a light-emitting diode (LED), an incandescent light, andthe like. When ink that is visible under ultraviolet light is used, anLED light source emitting light in the ultraviolet spectrum ispreferred. The mark reading unit 1060 is preferably placed at a stablelocation on the unwind stand 1010 or rewinder 1076. Suitable locationsinclude, for example, flat surfaces (e.g., web run 1052) and rolls(e.g., roll 1050). In the preferred embodiment shown in FIGS. 12A and12B, roll 1050 is a bowed roll. A bowed roll has an offset axis ofrotation, which stretches the paper web 102, 103 toward the ends of theroll. This roll may also be called a spreader roll, as it spreads thepaper. As a result, the bowed roll 1050 helps to ensure that paper web102, 103 is taut and moving at a consistent speed as it moves under themark reading unit 1060. The mark reading unit 1060 is connected to amark reading computer 922, which performs the mark identificationanalysis.

When a parent roll 191, 192 is loaded onto the unwind stand 1010 in theconverting line 1000, an operator may manually enter the rollidentification numbers into the PLC 924, which is then transmitted tothe master converting line computer 920. Alternatively, the mark readingunit 1060 and mark reading computer 922 may identify the parent roll191, 192 by reading a roll identification mark 610. Preferably, a parentroll 191, 192 is identified by reading the same roll identificationnumber multiple times to ensure statistical confidence of the numberread. Most preferably, the roll identification number is read twice fromtwo sequential roll identification marks 610. Once the parent roll 191,192 is identified, the parent roll identification number is transmittedto the master converting line computer 920. In either case, the masterconverting line computer 920 then retrieves from the roll server 914 thescored database associated with the identified parent roll 191, 192.When the roll server 914 transmits the scored database, the database is“checked out” from the roll server 914, and the scored database is“checked in” once the parent roll 191, 192 has been converted.

As the parent roll 191, 192 is unwound, the mark reading unit 1060 readsthe mark 610, 620 on the paper web 102 and passes the information to thePLC 924. When roll identification information is read, the PLC 924checks to ensure that the correct parent roll 191, 192 is identified.When location information is read, the PLC 924 adjusts the convertingline parameters based on the inputs for converting line controlassociated with that block 712 identified in the scored database.

We will now describe converting line control using the preferredembodiment of an action score and a quality score. In this approach,each time a location mark 620 is read, the master converting linecomputer 920 transmits to the PLC 924: (1) the location information inlinear feet associated with that mark (MD Footage), (2) the linearfootage of the next block 712 of the paper web 102 that has a non-zeroaction score, (3) the action score of the next non-zero block 712 of thepaper web 102, and (4) the quality score for the block 712 associatedwith the mark just read. The PLC 924 continuously counts the linearfootage of the paper web 102 being converted. This count is updated uponreceipt of the location information associated with the mark just read.The PLC 924 then calculates the distance remaining to the next non-zeroblock 712. The PLC 924 will also calculate, given the current operatingparameters (for example, speed), the distance required to execute theaction associated with the next non-zero block 712. The PLC 924 includesseveral factors in this calculation, depending upon the next action andspecific converting line. These factors include: deceleration rate for asplice, deceleration rate for stopping, deceleration rate to slow,target speed for slowing, and the like. The PLC 924 then compares thedistance remaining to the next non-zero block 712 to the calculateddistance required to execute the next action. If sufficient footage isstill available, the PLC 924 will continue converting at the currentoperating parameters and repeat the calculation. The PLC 924 willinitiate the next action when the current footage is within a bufferdistance of the calculated footage for the next action. We have foundthat it is beneficial to include buffer footage to prevent unintendedweb breaks from occurring because the PLC 924 waited to initiate actionuntil there is exactly the amount of footage required between thecurrent location and the next action point.

FIG. 13 shows an exemplary operator control screen 1100 for theconverting line PLC 924 that may be used with this implementation. Thecontrol screen 1100 may be implemented on any suitable device including,for example, a touch screen or an LED display that is operated by amouse and a key board. The control screen includes a roll map 1110. Inthis case, the roll map shows the first ply of a roll used in making amulti-ply paper product. The roll map includes a defect map 1112. Thedefect map 1112, like the defect map shown in FIG. 4, above, containsgraphical indications of defect positions. Each line in the defect map1112 indicates a different block 712 (FIG. 7). The action scoreassociated with each block 712 is also identified on the defect map1112. While any suitable means of indication may be used, a colored box1114 is along the side of each block is used in this embodiment. Here,an action score of zero is indicated by a green box 1114 and correspondsto normal operation of the converting line. An action score of oneresults in a stop or a splice command and is indicated by a red box1114. An action score of two slows the converting line and is indicatedby a yellow box 1114. A legend 1120 is provided to describe thegraphical indications of defects and the converting line actionsassociated with the colored boxes 1114. Also shown in the roll map 1110is the MD footage 1116 associated with each block 712 and, as anoperator aid, the diameter 1118 of the parent roll 190.

The control screen 1100 also allows for manual action overrides in asection 1130 of the control screen. The operator may review the upcomingblocks 712 and manually override the action score for that block. Theoperator may select a particular block 712 and then choose from presetactions in a drop down menu 1132. This section 1130 also includes a dropdown menu 1134 for the operator to give a reason for his/her change.These reasons may subsequently be used to adjust the rules for assigningconverting line control as discussed below. Once the operator hasselected an action and a reason for the change, the operator thenselects the apply button 1136. When the apply button 1136 is selected,the PLC 924 the updates the scored database with the manually appliedaction. We have found that it is beneficial to assign an alternate score(e.g., a three, a four, or a five) for manually input actions. Thisimproves subsequent analysis and feedback used in refining the rulesused to assign the action scores and quality scores. A status section1140 is also displayed on the control screen 1100. This section 1140gives an indication of the current footage, the footage at which the PLCwill take the next action (action footage), and the next action.

We will now describe converting line control using the alternateconverting line inputs of defect code and severity levels. When defectcode and severity level are used, the PLC 924 adjusts the convertingline parameters according to a predetermined set of rules. These rulesare established for each converting line to prevent a converting linefailure. For example, the PLC 924 may slow the converting line fromabout two thousand feet per minute to about one thousand five hundredfeet per minute for a defect code for holes having a severity level offive, or slow the converting line to about one thousand two hundred feetper minute for holes having a severity level of seven. The actions takenby the PLC 924 to adjust parameters may vary by converting line. Usingthe example of a defect code for a web break, the PLC 924 on oneconverting line may execute a splice to switch between parent rolls,because the converting line has a flying splice capability, but the PLC924 for a second converting line may stop the converting line for thesame defect code.

In the preferred embodiment shown in FIGS. 12A and 12B, the mark readingunit 1060 is positioned downstream from the parent roll 191 beingunwound. A particular block 712 (FIG. 7) of the paper web 102,therefore, has already traveled through a portion of the converting line1000 before the location information associated with that block 712 isread. If that particular block has defects, they may cause a web breakas the web passes one of the rollers 1041, 1043, 1045, 1046 upstream ofthe mark reading unit 1060. In this preferred embodiment, the PLC 924,therefore, sets the operating parameters of the converting line 1000based on the defect code and severity level for a predetermined numberof blocks 712 after the block 712 associated with the mark just read.

The PLC 924 may also consider several of the upcoming blocks indetermining how the converting line parameters are adjusted. As shown inFIG. 14, blocks eight and fifteen may have defects requiring theconverting line to slow to about one thousand five hundred feet perminute, and blocks eleven and twelve may have defects requiring theconverting line to slow to about one thousand two hundred feet perminute. To avoid rapid and successive changes in operating speed(non-preferred profile in FIG. 14), the PLC 924 may begin slowing theconverting line at block four to reach about one thousand five hundredfeet per minute at block eight and about one thousand two hundred feetper minute at block eleven, and then gradually increase speed from blocktwelve to reach full speed of about two thousand feet per minute atblock twenty (preferred profile in FIG. 14). Those skilled in the artwill recognize that the assignment of operating parameters may beperformed by the analysis tool and pushed to the converting line,instead of being performed at the converting line.

FIGS. 15A and 15B show an exemplary operator control screen 1200 for theconverting line PLC 924. FIG. 15A shows the left half of the controlscreen 1200 and FIG. 15B shows the right half. In this embodiment, theconverting line is creating a two-ply paper product and uses two parentrolls, one for the first ply and the other for the second ply. As withcontrol screen 1100, the control screen 1200 may be implemented on anysuitable device including, for example, a touch screen or an LED displaythat is operated by a mouse and a keyboard. The control screen 1200 hasthree major sections: operator controls 1210, the first ply roll map andaction registry 1220, and the second ply roll map and action registry1230. Each roll map and action registry 1220, 1230 contains a defect map1221, 1231. The defect map, as with the defect map shown in FIG. 4,above, contains graphical indications of defect positions. Each line inthe defect map 1221, 1231 indicates a different block 712 (FIG. 7). Eachaction registry 1222, 1232 contains two sub-registries. The first is anautomatic action registry 1224, 1234. This registry contains the actionsassigned to each block 712 by the PLC 1024 based upon the defect codeand severity level. The second is a manual action registry 1223, 1233.The control screen 1200 allows an operator to review upcoming blocks 712and to input manual actions in the manual action registry 1223, 1233. Anoperator may change input actions by selecting a block 712 and thenchoose one of the operator controls 1210. An operator may specify aslower speed by inputting the speed into the slow speed set point 1212and then pressing the slow button 1211. Alternatively, the controlscreen may have only one slow speed preset. The operator may input asplice or a stop by pressing the splice button 1213 or stop button 1214,respectively. The operator may clear the manually inputted action bypressing the clear action button 1215. The PLC 924 will control theconverting line by the actions in the automatic action registry 1224,1234 unless overridden by an action in the manual action registry 1223,1233.

In the present embodiment, the PLC 924 takes the actions assigned to ablock 712 that is a predetermined number of blocks 712 behind the markread by the mark reading unit 1060, as discussed above. On the controlscreen 1200 shown in FIGS. 15A and 15B, this is illustrated by mark readline 1241 and send action line 1243. The operator may select apredetermined number of blocks by changing values assigned to the lookahead distance 1242. In this embodiment, when a two-ply paper product isbeing created on the converting line 1000, the speed for the convertingline will be set for a particular segment by the slowest speed in theactive action registry for either ply. When there is a splice, however,the action will be taken for only one parent roll.

We will now describe a preferred embodiment of our invention withreference to FIGS. 16 to 19. In this preferred embodiment, the inputsassigned and used for converting line control are the action score andquality score. FIG. 16 is a flowchart showing an overall process flow ofour invention. As described in the embodiments discussed above, ourinvention is implemented to a paper machine 100, an analysis tool, and aconverting line 1000. Those skilled in the art will recognize that theanalysis tool may be co-located at either the paper machine 100 orconverting line 1000 or may be at a separate location. In our invention,a web is inspected at step S1310 and the results of the inspection areused to identify defects in the web at step S1320. Also, at the papermachine 100, the web is periodically marked and both the mark 210 andthe time of marking is recorded in step S1330. In step S1350, other webproperties 1340, such as tensile strength and basis weight (discussedabove), are used to aggregate the defects identified in step S1320 overa particular time interval. Also, in this step S1350, inputs forconverting line control (i.e., action score and quality score in thisembodiment) are assigned to a mark 210 applied to the web in step S1330.On the converting line 1000, the marks are read in step S1360. Theaction score, action footage, and quality score assigned to the readmark 210 are obtained in step S1370. In step S1380, the converting lineparameters, such as converting line speed, are adjusted based upon theinputs obtained in step S1370.

Steps S1310, S1320, and S1330 shown in FIG. 16 will now be described inmore detail with reference to FIG. 17. In step S1410, the web inspectionsystem detects candidate defects. The web inspection system thendetermines whether the candidate defect is a true defect or a falsedefect using, for example, the method described in U.S. Patent Appln.Pub. No. 2012/0147177, which issued as U.S. Pat. No. 9,172,916, (thedisclosure of which is incorporated by reference in its entirety). Forthose defects that are true defects, the defect properties such as sizeand position are determined by the defect inspection system in stepS1430. These defect properties for each true defect are then recorded indefect database 1400. The web is also marked with a roll identificationmark 610 at a set periodicity by a web marking unit 171, 172 in stepS1450. In step S1460, the roll identification mark 610 and the time themark is made on the web is then recorded in defect database 1400.Similarly, the web is marked with a location mark 620 in step S1470, andthen, in step S1480, this mark 620 and time of marking is recorded indefect database 1300. In the single mark embodiment, steps S1470 andS1480 may be omitted.

Step S1350 shown in FIG. 16 will now be described in more detail withreference to FIG. 18. In step S1520, the defect data from the defectdatabase 1300 and other paper web properties such as paper web moisturecontent 1511, paper web basis weight 1512, paper web tensile strength1513, the paper machine parameters used to derive web properties 1514,and TAPPI ID number 1514 are aggregated into a database and aligned instep S1530 within the database according to the master timestamp to forma consolidated database 1502. The consolidated database is then analyzedin step S1530 according to a predetermined set of rules to assign theaction scores and quality scores to each block of the parent roll. StepS1530 may be executed using the process described above in reference toFIGS. 9A to 9M. Then, as described in reference to FIG. 9N, the actionfootage is assigned in step S1540 to form the scored database 1504.These rules may be adjusted periodically in step S1550 based uponperformance data 1680 from the converting line 1000.

Steps S1360, S1370, and S1380 shown in FIG. 16 will now be described inmore detail with reference to FIG. 19. A mark reading unit 1060 readsthe mark 610, 620 in step S1610. The action score, quality score, actionfootage, and current footage is the obtained for the mark read in stepS1620 from the scored database 1504. The footage of the parent roll 190is continually being calculated as the parent roll is consumed in theconverting line 1000. This is referred to as the rewinder footage andtracked in step S1640. But, the rewinder footage is updated based on themark just read in step S1630 using the current footage obtained in stepS1620. As the rewinder footage is tracked in step S1640, the distancerequired to execute the next action based on the action score obtainedin step S1620 (“required distance”) is compared to the rewinder footagein step S1650. If the rewinder footage is less than or equal to therequired distance, the converting line 1000 takes the action assigned tothe action score in step S1660. If the rewinder footage is greater thanthe required distance, the converting line 1000 then check, if a newmark has been read by the mark reading unit 1060 in step S1670. If nonew mark has been read, the process returns to step S1640, but if a newmark has been read the process returns to S1620.

Additionally, performance data can be collected to improve theassignment of action scores and quality scores. In this case, thespecific location marks read are recorded in step S1682. In addition,converting line performance information is recorded in step S1684. Thisperformance information may include operating parameters of theconverting line, such as speed and when any unanticipated web failuresoccurred on the converting line or high speed video images of the webfailures. This information may also include manual override actionscores. The performance information and associated location marks 620may be recorded as converting line performance data 1680 and used toadjust the rules to assign actions, or assign fault codes and severitylevels (as discussed above).

We will now describe an alternate preferred embodiment of our inventionwith reference to FIGS. 20 to 22. In this preferred embodiment, theinputs assigned and used for converting line control are the fault codesand severity levels. This embodiment is similar to the embodimentdescribed above in reference to FIGS. 16 to 19. We will focus ourdiscussion of this alternate embodiment to the different features ofthis alternate embodiment, and we will use the same reference numeralsto reference the same or similar features.

FIG. 20 is a flowchart showing an overall process flow of our invention,similar to that shown in FIG. 16. In step S1710, other web properties1340 are used to aggregate the defects identified in step S1320 over aparticular time interval. The defect code and severity level are alsoassigned in step S1710. On the converting line, the marks read in stepS1360 are used to obtain the fault codes and severity, in step S1720. Instep S1720, the converting line parameters, such as converting linespeed, are adjusted based upon the inputs obtained in step S1730.

Step S1710 shown in FIG. 20 will now be described in more detail withreference to FIG. 21. Step S1520 is similar to that described above inreference to FIG. 18. Here, however, the defects and web properties areaggregated and aligned into consolidated database 1800. The consolidateddatabase 1800 is then analyzed in step S1810 according to apredetermined set of rules to assign inputs for converting line controlto each block 712 (FIG. 7) of the parent roll in the consolidateddatabase 1800. The predetermined set of rules may include those rulesdiscussed above in conjunction with the process to assign fault codesand severity levels. These rules may be adjusted periodically in stepS1550 based upon performance data 1960 from the converting line 1000.

Steps S1360, S1720, and S1730 shown in FIG. 20 will now be described inmore detail with reference to FIG. 22. A mark reading unit 1060 readsboth a roll identification mark 610 in step S1910 and a location mark620 in step S1920. In the single mark embodiment, only one mark is readin step S1910. In step S1930, the fault code and severity levels forupcoming blocks 712 are obtained from the consolidated database 1800.Then, converting line actions are assigned in step S1940 to each of theupcoming blocks 712 according to a predetermined set of rules for thatparticular converting line 100. Steps S1910 through S1940 are repeatedas successive marks are read on the paper web 102, 103. As each locationmark is read, the actions to adjust converting line parameters that areassociated with that mark are taken, in step S1950. As discussed above,the actions taken in step S1950 may be the actions assigned to a block712 a predetermined number of blocks from the mark read by the readingunit 1060.

Performance data can also be collected in this embodiment to improve theassignment of fault codes and actions taken by the converting line 1000.In this case, the specific location marks read are recorded in stepS1961. In addition, converting line performance information is recordedin step S1962. This performance information may include operatingparameters of the converting line, such as speed and when anyunanticipated web failures occurred on the converting line or high speedvideo images of the web failures. The performance information andassociated location marks 620 may be recorded as converting lineperformance data 1960 and used to adjust the rules to assign actions orassign fault codes and severity levels (as discussed above).

Although this invention has been described in certain specific exemplaryembodiments, many additional modifications and variations would beapparent to those skilled in the art in light of this disclosure. It is,therefore, to be understood that this invention may be practicedotherwise than as specifically described. Thus, the exemplaryembodiments of the invention should be considered in all respects to beillustrative and not restrictive, and the scope of the invention to bedetermined by any claims supportable by this application and theequivalents thereof, rather than by the foregoing description.

INDUSTRIAL APPLICABILITY

The invention can be used to produce desirable paper products, such aspaper towels and bath tissue. Thus, the invention is applicable to thepaper products industry.

We claim:
 1. A method of producing a paper product, the methodcomprising: (a) forming a paper web on a paper machine, the paper webincluding a plurality of sections; (b) analyzing the paper web with aweb analysis unit to perform at least one of inspecting the paper weband identifying properties in the paper web; (c) marking the paper webwith a plurality of marks, at least one mark being marked at each of theplurality of sections; (d) winding the paper web with the winder to forma parent roll after the paper web has been inspected and marked; (e)assigning a paper rating to each section of the paper web based upon theproperties in that section of the paper web that are identified in theanalyzing step; (f) unwinding a paper web from a parent roll on aconverting line having a plurality of operational parameters; (g)reading at least one of the plurality of marks with a mark reading unit;(h) obtaining the paper rating associated with the at least one markread by the reading unit; (i) changing at least one operationalparameter of the converting line based upon the paper rating; and (j)converting the paper web into a paper product.
 2. The method of claim 1,further comprising unwinding the paper web from the parent roll at aparent roll speed, wherein the changing step changes the parent rollspeed as the at least one operational parameter.
 3. The method of claim1, wherein the converting line comprises a first roller, a second rollerpositioned opposite to the first roller, and a nip formed between thefirst roller and the second roller, the nip having a plurality of nipparameters, the method further comprising passing the paper web throughthe nip, wherein the changing step changes at least one nip parameter asthe at least one operational parameter.
 4. The method of claim 1,wherein the converting line comprises a first roller and a secondroller, the method further comprising tensioning the paper web betweenthe first roller and the second roller to a paper web tension, whereinthe changing step changes the paper web tension as the at least oneoperational parameter.
 5. The method of claim 1, further comprisingunwinding a second paper web from a second parent roll, wherein thechanging step switches between (i) converting the paper web into thepaper product and (ii) converting the second paper web into the paperproduct, as the at least one operational parameter.
 6. The method ofclaim 5, wherein the converting line further comprises an unwind standthat holds both the paper web and the second paper web, the unwind standincluding a flying splice to switch from converting one of the paper weband the second paper web, wherein the changing step splices between thepaper web and the second paper web, as the at least one operationalparameter.
 7. The method of claim 1, further comprising: obtaining thepaper rating for at least one section of the paper web that is apredetermined number of sections after the at least one mark read by thereading unit; and changing the at least one operational parameter of theconverting line based upon the paper rating of the one section of thepaper web that is a predetermined number of sections after the at leastone mark read by the reading unit.
 8. The method of claim 7, furthercomprising inputting a manual rating that overrides the paper rating. 9.The method of claim 1, wherein the paper rating is assigned based on theinter-relationship of the web properties in one of the plurality ofsections of the paper web.
 10. The method of claim 1, wherein the webproperties include web defects.
 11. The method of claim 10, wherein theweb defects include at least one of a hole, a tear, a wrinkle, a webbreak, and a chemical coating streak.
 12. The method of claim 1, whereinthe web properties include at least one of moisture content, basisweight, and tensile strength.
 13. The method of claim 1, wherein thepaper rating is assigned based on the inter-relationship of the webproperties in multiple, adjacent sections of the paper web.
 14. Themethod of claim 13, wherein the paper rating is assigned by weightingeach of the multiple, adjacent sections of the paper web.
 15. The methodof claim 1, wherein the paper rating includes type information andseverity information.
 16. The method of claim 15, wherein the typeinformation includes at least one of a web break, a wrap, and quality.17. The method of claim 15, wherein the severity information is a valuefrom about 1 to about
 10. 18. The method of claim 1, wherein markingstep comprises marking the paper web with ink.
 19. The method of claim18, wherein the ink is visible under ultraviolet light.
 20. The methodof claim 13, wherein the at least one mark is coded to indicate aposition on the paper web.
 21. The method of claim 1, wherein themarking step includes: applying a first mark to the paper web, the firstmark (i) including a start position and (ii) being coded to convey anidentifier for the paper web; and applying a second mark to each sectionof the paper web as the at least one mark, the second mark (i) includinga start position, the start position of the second mark being apredetermined distance after the start position of the first mark, and(ii) being coded to indicate a position on the paper web.